One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,7,8,5)(9,10,12,14)(11,17,18,24)(13,21,20,16)(15,22,23,19)(25,26,29,32)(27,33,34,40)(28,36,37,31)(30,38,39,35)(1,3,4,8)(2,5,6,7)(10,14)(15,23)(16,21)(17,24)(27,34)(30,39)(33,40)(35,38)(9,11,12,18)(10,15,14,23)(13,22,20,19)(16,24,21,17)(28,37)(31,36)(33,40)(35,38)(25,27,29,34)(26,30,32,39)(28,38,37,35)(31,40,36,33)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.